[DonCorazon]

Pretty simple to me: play to win, and when it looks like you cannot win, play to last as long as you can, maybe things will change and your prospects will turn around. Remember one game where a player was immediately sieged and almost domkilled, but incredibly managed to slay the offending carrion dragon with a handful of units and despite the horrific start went on to become one of the leading contenders. Ironically, the aggressor in that game quit as soon as his pretender was killed.

I think if you follow those guidelines, you will pretty much be following everything Micah said e.g. you wouldn't give up your last VP since that would be suicide.